1. FIELD OF THE INVENTION
The present invention relates to an apparatus for automatically mounting electronic components wherein a take-out nozzle is rotated by a nozzle rotating unit based on data on an angular position assumed by each chip-shaped electronic component firmly held on the take-out nozzle, the angular position being recognized by a recognizing unit, in order to perform a correcting operation so as to allow the electronic component to assume an adequate angular position, and after completion of the correcting operation, the respective electronic components are mounted on a printed-circuit board.
2. DESCRIPTION OF THE PRIOR ART
A typical conventional apparatus of the foregoing type for automatically mounting electronic components has been disclosed, e.g., in an official gazette of Japanese Laid-Open Patent NO. 55998/1987. According to this prior invention, the apparatus includes nozzle selecting means for selecting one of plural kinds of of suction nozzles to be used by rotationally driving one of a plurality of turn holders corresponding to the selected suction nozzle, the turn holders being arranged round the outer periphery of an intermittently rotatable supporting member so that the suction nozzles are rotatably held on the turn holders while a distance corresponding to a pitch of intermittent rotary movement of the supporting member is held between adjacent turn holders, rotational driving of the turn holder being effected corresponding to a position on the passage for the turn holders where intermittent rotational movement of the turn holders is interrupted, component feeding means for feeding an electronic component to the selected suction nozzle thereby to firmly hold the electronic component on the turn holder under the effect of air suction, position detecting means for detecting the present angular position assumed by the electronic component firmly held on the suction nozzle, and nozzle rotating means for rotationally driving the suction nozzle having the electronic component firmly held thereon under the effect of air suction thereby to set or correct the present angular position of the electronic component based on data derived from the detection of the present angular position assumed by the electronic component. The aforementioned plural means are arranged one after another as seen in the direction of turning movement of the intermittent rotary supporting member so that the electronic components are successively mounted on the printed-circuit board.
With the conventional apparatus as constructed in the above-described manner, in a case where data on the present angular position assumed by the electronic component firmly held on the suction nozzle do not coincide with data on an angular position preset for the electronic component, the suction nozzle is rotated by the nozzle rotating means, until the data on the present angular position become coincident with data on the preset angular position of the electronic component. With some electronic component, however, even when it should be mounted on the printed-circuit board with a high accuracy by rotating the suction nozzle, there arises a problem that the electronic component is incorrectly mounted on the printed-circuit board at an angular position offset from the preset angular position, because it has been not heretofore confirmed that the electronic component is exactly mounted on the printedcircuit board by rotating the suction nozzle.
Another conventional apparatus of the aforementioned type is disclosed in an official gazette of U.S. Pat. No. 4,747,198. According to this prior invention, after the present angular position assumed by an electronic component is recognized, a suction tube is rotated so as to eliminate positional deviation of the electronic component. However, it has been found that the same problem as described above arises likewise with this conventional apparatus.